Multicast streaming services provide for the continual feed of streaming data, including video, over a network to many different users. The most common application is streaming video across a network system. Audio streaming is another common application. However, these streaming application types are not intended as a limitation. Typically, a particular data stream is multicast from a single server over a network. This allows many people to receive and view the same program simultaneously.
If however, the server becomes unavailable, then the multicast stream which is being served from the server will also be unavailable, thus leading to an outage of service.
Increasingly, the lines between cable television service and serving a data stream over the Internet is becoming blurred. More and more, television-like content is being served to users of the Internet. This is becoming increasingly so in an era where bandwidth is increasing, and is readily available to Internet users. Today, Internet cable, DSL, and other types of high bandwidth lines are readily available to Internet users. Such users are demanding more and more content.
When a web based asset is used to stream video to Internet users, especially multiple users, there are generally two schemes that are employed. First, a unicast of the data stream is made to a single user. In a unicast situation, a single user connects to a website having program content. Upon demand, that program content is served by the web server to the individual user. When multiple users desire a particular program at different times, multiple unicasts of the data are made by the server. However, a single server can only serve a finite number of unicast streams of a given program content.
Multiple streaming servers are used to load balance unicast data to many individual users. If a particular server fails, each user suffers an outage, albeit of differing content initiated at different times. Frequently multiple streaming servers are used in order to achieve load balancing and to allow multiple unicast streams of the same web asset. This approach works well when an equal number of video streams are served from each of the servers. However, if any server goes down, the individuals who are being served from that server will have their service disrupted.
When a streaming server is distributing a video stream in a multicast mode (that is, simultaneous streaming of a video stream by multiple users), rather than in multiple unicast streams, the load on the server is relatively low. This is because a single stream per program is being broadcast by the server to multiple users, therefore multiple interactions with the server are not required for a single program. In a multicast situation, load balancing is not as much of an issue and therefore, multiple servers are not required. These relatively unused stream server resources can be used to increase the program availability by providing redundant servers of the same content.
What would be particularly useful is a system which allows for the unicast or multicast of a video stream with the reliability that is associated with redundancy in the system.